Apache SpamAssassin: Difference between revisions

Revision as of 08:42, 29 May 2025

Revision as of 16:48, 29 May 2025

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* Bayesian filtering support (version 2.50, February 2003)<ref name="sa-2.50">{{cite web|title=SpamAssassin 2.50 Released|url=https://spamassassin.apache.org/news/2003-02-25.html|website=SpamAssassin|date=2003-02-25|access-date=2023-08-23|archive-url=https://web.archive.org/web/20030301000000/https://spamassassin.apache.org/news/2003-02-25.html|archive-date=2003-03-01}}</ref>

* Network-based tests and distributed checksum systems

* Support for SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail)<ref name="email-auth-book">{{cite book|last=Levine|first=John|title=Email Authentication: What It Is and Why It Matters|publisher=Freepress|year=2018|isbn=978-1983433337|pages=89-9289–92}}</ref>

===Apache Foundation adoption===

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===Rule types===

SpamAssassin employs several categories of tests:<ref name="packt-guide">{{cite book |first1=Alistair |last1=McDonald |title=SpamAssassin: A Practical Guide to Integration and Configuration |publisher=[[Packt|Packt Publishing]] |edition=1st |pages=45-6745–67 |date=September 27, 2004 |isbn=978-1-904811-12-1}}</ref>

'''Header tests''': Examine email headers for signs of forgery, suspicious routing, or spam software fingerprints.

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===Network-based filtering===

SpamAssassin supports numerous network-based tests that leverage the collaborative nature of spam fighting:<ref name="network-tests">{{cite book|title=Combating Spam and Viruses|last=Wolfe|first=Paul|publisher=CRC Press|year=2016|isbn=978-1498749732|pages=123-145123–145}}</ref>

'''DNS-based blacklists (DNSBLs)''': Queries against lists of known spam sources, including:

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===Authentication verification===

SpamAssassin verifies several email authentication standards:<ref name="auth-methods">{{cite journal|title=Email Authentication Mechanisms: DMARC, SPF and DKIM|journal=Journal of Computer Security|volume=27|issue=2|pages=179-202179–202|year=2019|doi=10.3233/JCS-181144|last1=Durumeric|first1=Zakir|last2=Adrian|first2=David|doi-broken-date=29 May 2025 }}</ref>

* '''[[Sender Policy Framework|SPF]]''': Validates sending server authorization

* '''[[DomainKeys Identified Mail|DKIM]]''': Verifies cryptographic message signatures

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==Performance and scalability==

SpamAssassin's performance depends heavily on configuration and deployment method:<ref name="performance-study">{{cite conference|title=Performance Analysis of Open Source Anti-Spam Systems|conference=Annual IT Security Conference|date=2018-06-15|pages=234-241234–241|last1=Thompson|first1=Sarah|last2=Kumar|first2=Raj}}</ref>

'''Processing speed''':

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==Limitations and criticism==

Despite its widespread use, SpamAssassin has several limitations:<ref name="limitations-analysis">{{cite journal|title=Comparative Analysis of Anti-Spam Technologies|journal=Network Security|volume=2021|issue=3|pages=12-1812–18|year=2021|doi=10.1016/S1353-4858(21)00028-3|last=Chen|first=Wei}}</ref>

===Performance concerns===

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* {{cite book|title=Anti-Spam Techniques Based on Artificial Immune System|last=Tan|first=Ying|publisher=CRC Press|year=2016|isbn=978-1498725387}}

* {{cite book|title=Email Security with Cisco IronPort|last=Bochenek|first=Chris|publisher=Cisco Press|year=2013|isbn=978-1587142925}}

* {{cite journal|title=Machine Learning for Email Spam Filtering: Review, Approaches and Open Research Problems|journal=Heliyon|volume=5|issue=6|year=2019|doi=10.1016/j.heliyon.2019.e01802|last1=Dada|first1=Emmanuel Gbenga|pages=e01802 |doi-access=free |bibcode=2019Heliy...501802D }}

==External links==